In many applications that relate to assessment of movement of the body of a human or other mammal, rehabilitation, strain or load monitoring, sports assessment, as well as design and construction of workplaces, an ability to make assessments about an activity may be improved by knowing a general orientation of the body of the human or mammal. This is because the forces acting on the trunk or any limb of the body may in general be significantly affected by the orientation of the body.
A number of physiological and biomechanical changes occur when for example a body moves from one orientation to another, e.g., sitting to standing or vice versa. In a biomechanical context, this movement may lead to changes in angular displacement of various anatomical landmarks with respect to one or more reference planes. Identification of body orientation may therefore require measurement of angular displacement with respect to a frame of reference. Angular displacement may be measured using position sensors such as accelerometers which provide a position referenced to gravity, magnetometers which provide a position referenced to earth's magnetic field, gyroscopes and/or optical sensors. The present invention may use a position sensor to detect angular displacement of one or more points on the body of a mammal such as one or more points on the spine and may use the displacements to identify various orientations of the body.